A. Field of the Invention
The present invention generally relates to a guide tube with favorable flexibility and water-tightness, or more particularly, to a guide tube which is easily inserted with an endoscope into a body cavity or is smoothly inserted into bronchia as an anesthetic tube.
B. Description of the Prior Art
An endoscope is an optical instrument which utilizes flexible optical bundles for observing means in order to transmit an image of an object caught at a forward portion to an eyepiece of a grip and is used for inspecting or treating a cancer or a polyp in a body cavity. The forward portion with angle deflective means and a flexible sheath composed of spiral wires are inserted into the body cavity for inspection. But, direct insertion of these elements frequently results in bleeding or a difficulty in insertion, because the inner side of the body cavity is complicated.
For this reason, a guide tube is attached round the forward portion and the flexible sheath when inserting them into the body cavity in order to prevent an injury or to have a smooth insertion. In addition, the endoscope can be inserted several times by way of the guide tube, if it is left in the body cavity.
In an anesthetic operation, an anesthetic drug is forwarded into the lungs by way of an anesthetic tube which is inserted into the bronchia.
Accordingly the, above-said guide tube or the anesthetic tube must be in the first place smooth between the body cavity and also be good in water-tightness for shutting off a body fluid, cleanser, or the anesthetic drug. Further, the guide tube must bend itself continuously keeping its tubular shape.
Formerly, a synthetic resin tube was used for the guide tube which is indeed good in its water-tightness, but the tubular form is constricted at the minimum point of the radius of curvature as shown in FIG. 1, when it is inserted in the complicated body cavity. Further, insertion in a body cavity is difficult when the tube is too thick in order to cope with above-said defect.
While a vinyl chloride tube is formerly used for an anesthetic tube, its flexibility is not so good and high-temperature sterilization is not possible due to the fact that it begins to soften at 80 degrees.